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Re: Good article on the gas gusseling PT boats.

Yes, but thats at combat speed, patrol speed often just used one engine at much reduced throttle, that gave them 8 or 9 knots on 20 gals an hour or so. Several days worth.
Some very similar motor patrol boats built in New Zealand convoyed up to Fiji and across to the Solomons during the war, carried two of their props on the afterdeck and just ran on one engine.
Common practice when moving a Pt or similar over long distances.

Re: Good article on the gas gusseling PT boats.

Besides fuel conservation, running slowly on one engine made for less wake. The wake at full bore all three engines was visible for miles and miles from the air.

Surely not?

"Travel is fatal to prejudice, bigotry and narrow-mindedness, and many of our people need it sorely on these accounts. Broad, wholesome and charitable views of men and things cannot be acquired by vegetating in one little corner of the earth all one's lifetime" Mark Twain... so... Carpe the living sh!t out of the Diem
I'd rather look back at my life and say "I can't believe I did that" instead of being there saying "I wish I'd done that"

Re: Good article on the gas gusseling PT boats.

Ian the Greater is right to suspect a bit of hyperbole on my part, but the wake from all three engines running, especially at night with the bioluminescence, was an issue. Aquajets from high speed catamaran ferries leave a longer wake. I’ve used them as the trail through fog into Nantucket up to a quarter hour after hearing the ferry pass, which makes that visible trail about five miles long.

“Speed had a disadvantage. The boats did have a rather large wake. As the book Motor Torpedo Boats, Tactical Orders and Doctrine notes:
1202. The wakes of motor torpedo boats at high speeds are visible considerable distances, both from the air and surface. The wake of center engine is less visible than that of wing engines. These factors should always be considered when planning operations unless satisfactory wake camouflaging apparatus is installed.”https://blog.usni.org/2009/09/22/the...ttoral-warfare

Re: Good article on the gas gusseling PT boats.

Re: Good article on the gas gusseling PT boats.

Originally Posted by Ian McColgin

Ian the Greater is right to suspect a bit of hyperbole on my part, but the wake from all three engines running, especially at night with the bioluminescence, was an issue. Aquajets from high speed catamaran ferries leave a longer wake. I’ve used them as the trail through fog into Nantucket up to a quarter hour after hearing the ferry pass, which makes that visible trail about five miles long.

“Speed had a disadvantage. The boats did have a rather large wake. As the book Motor Torpedo Boats, Tactical Orders and Doctrine notes:
1202. The wakes of motor torpedo boats at high speeds are visible considerable distances, both from the air and surface. The wake of center engine is less visible than that of wing engines. These factors should always be considered when planning operations unless satisfactory wake camouflaging apparatus is installed.”https://blog.usni.org/2009/09/22/the...ttoral-warfare

Re: Good article on the gas gusseling PT boats.

As I understand it from reading PT vets' accounts, the wing props caused the most visible turbulence and aeration of the water. These boats could run at almost twnty knots on the central engine alone and often moved along at ten or so which left an even more subtle and transitory wake. All three engines and maximum speed were most consistently used during actual attack.

Re: Good article on the gas gusseling PT boats.

Just an aside, one interesting and odd difference: The British MTB and German E Boats used in the North Atlantic were displacement hulls of remarkable efficiency and, for their size, considerable range. The US PT boats, operating mostly in the South Pacific, were planing hulls and had far less range. Meanwhile, it seems that British capital ships had considerable less range than US capital ships. It makes sense given history and missions before the war, but does seem odd.

Re: Good article on the gas gusseling PT boats.

Aquajets from high speed catamaran ferries leave a longer wake. I’ve used them as the trail through fog into Nantucket up to a quarter hour after hearing the ferry pass, which makes that visible trail about five miles long.

That's a handy trick, but accounting for the drift of that wake, from any current, must be an entertaining bit of navigation in its own right, yes?

Re: Good article on the gas gusseling PT boats.

Ian the British MTB/MGB were planing hulls similar to the PT boats (the first Elco boats were British design, later modified by Elco). The German S boats (the Brits called them E boats for some reason although every one had a large S and a number on the sides) were displacement hulls with max speeds similar to the Allied planing boats, although they had double the power and diesel engines. Also they were much more seaworthy and could maintain much higher speeds in adverse conditions.

Re: Good article on the gas gusseling PT boats.

Thank you Graeme. Further googling 'british wwii mtb' helped me see how right you are here.

Around here and around Boston Harbor, where I have used fastferry wakes, the current is not such a problem because - just as it happens - places of strong currents have most ferry routes with or against the current and where the boats operate at speed across the currents they are in more open waters with currents down no higher than three knots.

Re: Good article on the gas gusseling PT boats.

Originally Posted by Graeme Forrest

Ian the British MTB/MGB were planing hulls similar to the PT boats (the first Elco boats were British design, later modified by Elco). The German S boats (the Brits called them E boats for some reason although every one had a large S and a number on the sides) were displacement hulls with max speeds similar to the Allied planing boats, although they had double the power and diesel engines. Also they were much more seaworthy and could maintain much higher speeds in adverse conditions.

E-boat was a British designation for enemy. They had 3 diesels producing 3980 hp, with a speed of 43 knots. The British Power Boat MTB's were 71' boats which were the basis for the Elco boats. They ran three Packard 12 cyl but for silent running had a single flat head ford v8. Vosper also built an MTB. Fairmile D or dog boats were larger vessels but not as fast 115' long running four 12 cyl packards developing a total of 5000 hp and a top speed of 29knots.

Re: Good article on the gas gusseling PT boats.

When I was a kid, maybe 1970-73, our family used to go deep sea fishing out of Little Pee Dee river, SC. I remember one larger head boat, named the Hurricane, as I recall. Typical displacement deep see fishing boat. But one year Dad bought us tickets aboard what I recall him telling me was a WWII PT boat that had been converted to fishing. I just remember holding onto the railing tight as that boat got up on plane with the deep roar of the engines. Does anyone know of this boat?

Re: Good article on the gas gusseling PT boats.

In the late 1940's I was aboard a PT conversion air rescue boat out of Myrtle Beach Army Air Base while on Civil Air Patrol Cadet training. Had no reference at the time but it was darn fast and pretty rough ride. Later wandered through a PT graveyard in Pearl Harbor where many PT boats went to die. Saw one PT in Nassau that had been fitted with a single diesel but know nothing else about it. Our PT boats were largely ineffective in battle. In any water other than flat, Japanese destroyers could outrun them. Had a habit of breaking internal frames at speed in waves due to a too flat bottom and the high weight of armament.

Re: Good article on the gas gusseling PT boats.

The WWI MTB's were really interesting: stepped hulls which allowed high speeds with heavy power to weight ratio engines. Stepped hulls require great weight discipline and careful fore and aft weight distribution which is why once engines got big enough they were put on the shelf except for flying boats and raceboats. There is a Faulkner short story about these MTB's called Turnabout, and I think Fox has some stuff in his powerboat book. Poking around on the internet I find these were built by Thornycroft and called CMB's. What is impressive is the speeds and sizes obtained with little power.

Re: Good article on the gas gusseling PT boats.

There is a surviving WW1 CMB awaiting restoration at Chatham dockyard, i believe she is a 55 ft version. Rolled deck edge, single step with twin stern gear that is a work of art in bronze. There is a smaller 40 ft CMB at Duxford, http://www.iwm.org.uk/collections/item/object/30004029 ,

Re: Good article on the gas gusseling PT boats.

Originally Posted by keith66

There is a surviving WW1 CMB awaiting restoration at Chatham dockyard, i believe she is a 55 ft version. Rolled deck edge, single step with twin stern gear that is a work of art in bronze. There is a smaller 40 ft CMB at Duxford, http://www.iwm.org.uk/collections/item/object/30004029 ,

Re: Good article on the gas gusseling PT boats.

Pete I understand the CMBs did indeed slide the torpedos over the stern then quickly turned aside as the torpedo ran at similar speed to the boat. Apparently the installation was much lighter than contemporary torpedo tubes, weight being critical to the performance of such boats.

Re: Good article on the gas gusseling PT boats.

Originally Posted by Graeme Forrest

Pete I understand the CMBs did indeed slide the torpedos over the stern then quickly turned aside as the torpedo ran at similar speed to the boat. Apparently the installation was much lighter than contemporary torpedo tubes, weight being critical to the performance of such boats.

OMG, what could possibly go wrong! I was thinking perhaps they stopped, pulled it alongside, and aimed it before pushing the Go button. That didnt seem like a very smart wartime strategy, but I didnt consider pushing the torp over the stern while under way, and trying to outrun it.

Re: Good article on the gas gusseling PT boats.

Originally Posted by epoxyboy

OMG, what could possibly go wrong! I was thinking perhaps they stopped, pulled it alongside, and aimed it before pushing the Go button. That didnt seem like a very smart wartime strategy, but I didnt consider pushing the torp over the stern while under way, and trying to outrun it.

Pete

You didn't outrun the torp, you put her hard over. Find the William Faulkner story Turnabout.